The Mysterious Tanzanite

I think every gem dealer has a gem that she/he likes the most. Tanzanite for me is the essence of gems, my blue love, my true love of the mineral world, and yes, like a real lover, it does not always behave the way we expect it to.

Tanzanite, the birthstone for December, is fascinating as a gem and as a gem product. In nature most tanzanite rough is found in brown and purple colors, but after a short and not very sophisticated heating process, most turn into beautiful blue-violet of various intensities.

The history of tanzanite began in the late 1960s when Tiffany introduced this fine stone to the international market by launching a campaign. The gem was accepted with great enthusiasm and fetched very high prices, well over $1,000 a carat for fine,

large pieces. But due to unstable supplies, the market was limited mainly to collectors.

For the last 4 decades I have been traveling to Kenya and the mines in the Merelani hills in Tanzania where conditions in the early days were terrible, buying in the bush from the Masai miners and exporting officially to the west.

I have spent years refining the tanzanite heating process, including a custom-made computer-controlled oven with many stages and properties, only to find, fairly late in life, that this gem, which is my greatest love in the world of gems, behaves at its best when simply cooked on a fire or gas stove packed in a cigarette paper!

I first arrived in the US market in the late 1970s, with calibrated tanzanites, beautifully cut in our lapidary in Israel, but many dealers were hesitant to buy this soft gem. 6+ on the Mohs scale of hardness and in fact some call it, soft sapphire.

The 1980s saw a surge of supply from the mines, which resulted in greater recognition and appreciation of the gem. By the late 1980s, supply and demand were both high. Prices were attractive resulting in many designers using this remarkable gem as a centerpiece for their jewelry. The 1990s saw the golden era of tanzanite as a commercial product.

Outstanding tanzanites were being used for fine quality jewelry, but on the other hand, inferior qualities of tanzanites, pale or too violet, which were once considered to be too poor for use in jewelry, are quite commonly used today. Parcels of tanzanite cut in calibrated sizes are in high demand.

Because color is so dominant in jewelry today, large, colorful, sapphire blue, natural stones at a reasonable price are only feasible using tanzanite.

The newest trends in fashion brought with them the desire for natural non-heat gems, “you look your best when you are natural”.

My son, Kobi and I were the first in the industry to call these non-heat natural colors, (pleochroic colors including greens, blues, lavender and pinks,) Fancy Tanzanite... like Fancy color Diamonds. For us they are the Fancy color of the gem world...

Let’s not forget that tanzanite does not have the thousands of years history and reputation that sapphire has, hence it is more sensitive to changes. However, I believe that the fact that there is only one locality in which the stone is found, coupled with the relatively small supply, and the ever-growing demand and interest of the world market, and the fact that the Holy Bible mentioned only one big flood, tanzanite’s place in the gem-world is secured for many years to come.

Menahem Sevdermish, F.G.A, President